"It means that 10% ballistic gelatin ALREADY FIGURES IN the density of bone, along with all other tissue types in the body."

Brass Fetcher or Mr. Irwin and a plastic garbage can full of water. I'll stick with Brass Fetcher. The correlation is approximately 2" of water equals 1" of 10% ballistic gelatin which does not have anything to do with bone simulation, but soft tissue. So, no you are wrong. This is from the link above, and makes sense, where you are flat out wrong:

"Ballistic gelatin is an industry-standard medium used for evaluating the terminal performance of hunting and self-defense ammunition. Gelatin blocks offer many advantages in this role – it is a highly viscous liquid, offering a density close to that of human body fluids and the low-velocity characteristics of muscle tissue. It is a highly consistent material, which makes it very useful for making accurate measurements of damage done to the gelatin by a bullet penetrating soft tissue only.The critical areas of the body are generally protected in some manner by the presence of bone immediately behind the skin. The large percentage of the vital areas of the chest that are protected by the rib cage and sternum make it desirable to simulate bone and then the soft tissue behind the bone. A priority of this report was in choosing a caliber and ammunition that was relevant to both civilian law enforcement and
civilian gun owners. We evaluated several popular .38 Special JHPs from a common CCW firearm – a Smith and Wesson 642 with 1 7/8” barrel length.
Bone simulation was effected by placing a bone simulant plate, produced by Synbone AG of Switzerland, in front of blocks of 10% ballistic gelatin (Figure 1.) Tested plates were 6mm ( ¼” ) thick and covered by a rubberized ‘skin’ layer. Product number of these plates is PR0114.G. Density for the tested
samples came out to be 816 kg/m 3 and the failure mode for these was ‘brittle’ failure, similar to bone.

BTW, from Wikipedia:

Ballistic gelatin is a testing medium scientifically correlated to swine muscle tissue (which in turn is comparable to human muscle tissue), in which the effects of bullet wounds can be simulated. It was developed and improved by Martin Fackler and others in the field of wound ballistics.[1][2][3] Ballistic gelatin is a solution of gelatin powder in water. Ballistic gelatin closely simulates the density and viscosity of human and animal muscle tissue, and is used as a standardized medium for testing the terminal performance of firearms ammunition. While ballistic gelatin does not model the structure of the body, including skin and bones, it works fairly well as an approximation of tissue and provides similar performance for most ballistics testing. Ballistic gelatin is used rather than actual muscle tissue due to the ability to carefully control the properties of the gelatin, which allows consistent and reliable comparison of terminal ballistics.

The other problem with using ONLY gelatin is that bullets do funny things when encountering bones, especially bullets traveling less than 900-1000 fps. Gelatine certainly has its place, we should use every tool available.

Not sure where you are getting you information/"science" but according to Fackler:

"The test of the wound profiles’ validity is how accurately they portray the projectile-tissue interaction observed in shots that penetrate the human body. Since most shots in the human body traverse various tissues, we would expect the wound profiles to vary somewhat, depending on the tissues traversed. However, the only radical departure has been found to occur when the projectile strikes bone: this predictably deforms the bullet more than soft tissue, reducing its overall penetration depth, and sometimes altering the angle of the projectile’s course. Shots traversing only soft tissues in humans have shown damage patterns of remarkably close approximation to the wound profiles.

The bullet penetration depth comparison, as well as the similarity in bullet deformation and yaw patterns, between human soft tissue and 10% ordnance gelatin have proven to be consistent and reliable. Every time there appeared to be an inconsistency…a good reason was found and when the exact circumstances were matched, the results matched. The cases reported here comprise but a small fraction of the documented comparisons which have established 10% ordnance gelatin as a valid tissue simulant.

Gotcha. If I get a chance, I'll buy another box to test. I suspect that the bullet *would* work correctly in bare gelatin even at low velocity, which invites the question of what test procedures they used to determine the velocity window. I would really like to see a professional test of this stuff at low velocity, with denim.

No, it does NOT make any sense at all, because the people who did this obviously didn't pay much attention to the entire development and selection of ballistic gelatin.

The important phrase in all of this is Average Mean Density.

Does anyone know why that's important, or what it means?

It means that 10% ballistic gelatin ALREADY FIGURES IN the density of bone, along with all other tissue types in the body.

People who don't understand that very important fact have, for nearly 30 years, been looking at the FBI gelatin protocols and getting a very dim flicker in their eyes and exclaiming "My God! There's no bone! It's not right! It can't be right! I'll get some bone, cast it into gelatin, and that will make it right!"

No, no it won't make it right, anymore than sticking a plate of bone simulant in front of a block of 10% gelatin (remember average mean density) will somehow produce more realistic tests.

By adding extra bone in front of, behind, or inside a block of 10% ballistic gelatin, that immediately renders the average mean density wrong.

At that point the ONLY valid data you might get is if you intend to be using those bullets against someone who is partially fossilized.

There's a damned good reason why 10% ballistic gelatin is pretty much the worldwide forensic standard. FBI uses it, and ever major ammunition company uses it.

Why do they use it?

Because 10% ballistic gelatin (without extra bones, bone simulants, etc.) produces test results that most closely match -- BY FAR -- the results seen in actual shootings. INCLUDING shootings in which these bullets hit bone.

Oddly enough, though, what have people who don't understand the concept of average mean density found time and time again over the years when they shoot 10% ballistic gelatin in which there is extra bone or bone simulants?

They find that their results don't match either industry test results OR the results seen in actual shootings.

So, I say once again, this particular "test" is flawed and useless because the individuals doing the "testing" don't understand what they're trying to test, or why 10% ballistic gelatin, on its own, is the most valid and most repeatable testing medium there is.

The "bone simulant" also plugs the expansion cavity of the JHPs making it impossible for them to fill with the gelatin test medium in order to produce the hydraulic forces that drive bullet expansion. We do not have bony plates on our skins/bodies.

"It means that 10% ballistic gelatin ALREADY FIGURES IN the density of bone, along with all other tissue types in the body."

Well, we know that is wrong for a fact. People don't have skeletons, right? Even the great Fackler recognized this in his discussion of ballistic gelatin. The earth is not flat and we know for a fact that ballistic gelatin does not consider or emulate anything other than soft tissue according to Fackler and everyone else, except here in pretend world. When we reach the realm of fantasy, enough is enough. Sycophant.

Fackler: "However, the only radical departure has been found to occur when the projectile strikes bone: this predictably deforms the bullet more than soft tissue..."

Well, I spent the better part of my Sunday going through a lot of material trying to find the references that noted that ballistic gel was developed to emulate the average mean density of all tissue in the body and.... nothing.

I know I read a treatise on that years ago, but I don't know where anymore.

That said, I reiterate that the use of ballistic gelatin WITHOUT bone, bone simulant, bone through the nose, whatever, provides the single most reliable and realistic indicator of what happens when a particular bullet hits the human body.

That's been seen time and time again in comparison of testing data to actual shootings, and the only thing that casting bone or bone simulant into a block of gelatin does is... skew the results.

Bone simulant has been available for at least 40 years, real bone even longer. One really has to wonder why bone or bone simulant is not used in any of the industry or forensice protocols.

Actually, one doesn't have to wonder that.

It skews the results from what is seen in actual shootings, which means that its value as a testing medium... isn't valuable at all.

Martin Fackler is a medical doctor, combat surgeon, and has probably seen more wounds caused by actual projectiles that the rest of us combined.

One would think that, give the availability of bone simulant in the 1980s when the gelatin testing protocols were being developed that, if it offered anything of value, it would have been included in the standardized testing regime.

The fact that it wasn't should be a pretty good indicator of what value it might bring.

And yes, Mr. Mortimer. People do have skeletons. They just don't have exoskeletons, as Brasscatcher's tests would seem to indicate.

Even more interestingly, your quote from Fackler is particularly interesting because it appears to fly in the face of what Brasscatcher's "found" in their "testing."

And, you know, I just had another thought, too...

There's no indication of how brasscatchers prepared the bone simulant. Did they use it dry?

Living bone contains a significant quantity of water. Think about that.

__________________
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza

"Bone simulation was effected by placing a bone simulant plate, produced by Synbone AG of Switzerland, in front of blocks of 10% ballistic gelatin (Figure 1.) Tested plates were 6mm ( ¼” ) thick and covered by a rubberized ‘skin’ layer. Product number of these plates is PR0114.G. Density for the tested
samples came out to be 816 kg/m 3 and the failure mode for these was ‘brittle’ failure, similar to bone."

Ballistic gelatin does not reproduce bone or skin, just soft tissue, very accurately, according to Fackler. Until we swerved off into this issue, the only point I was trying to make, was that the 135 grain Gold Dot +P does not work so well in bare gelatin and the Corbon 110 grain DPX does. In addition, the DPX performed best with the bone simulant, a test that apparently does plug up a hollow-point bullet as most every bullet failed. Again, if I were looking for reliable expansion out of a .38 Special, and I'm not, I would use the DPX. Heavy clothing, and drywall and other barriers will plug up hollow-points, these are all "exo-barriers" and Brass Fetcher did attempt to simulate skin as well as bone as indicated above. Ballistic gelatin does not reproduce skin and bone. I'll stick with a hard cast wadcutter and a max meplat out of a .38 Special, which will have trouble expanding any bullet while providing adequate penetration in the first place. I'll take two feet of penetration with a standard pressure wadcutter lilke the 150 grain Buffalo Bore.

My question remains, as I suspect that dry bone simulant would produce significantly different results from wet bone simulant, just as bullet expansion differs wildly when shooting into dry newspaper vs. soaked newspaper.

A total of two shots from the original poster doesn't adequately test the 135-gr. Speer bullet, or any bullet, for that matter. I think we both know that, especially given the wide range of both test results and a more limited number of shooting results with that bullet that show markedly different performance.

__________________
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza

"My question remains, as I suspect that dry bone simulant would produce significantly different results from wet bone simulant..."

I just don't have the inclination to investigate the Swiss company in question, or the specifications of the product, but I would speculate that the product is a decent/excellent bone simulant, and probably accounts for moisture content, and as noted is comparably "brittle" as "real" bone. It does appear to plug bullets. Brass Fetcher provides a very detailed explanation of what they did and why they did it in terms of testing. As for Fackler not attempting to use any variations on ballistic gelatin testing, other than bare, the FBI and many others have recognized that adding clothing, drywall, sheet metal, glass, plywood, whatever, is real world. I appreciate all that Brass Fetcher has done and is doing in ballistic testing. Fackler's comment above on bullet/bone interaction is interesting, in that he calls it a "radical departure" from simple soft tissue, "when the bullet hits the bone" -

Fackler: "However, the only radical departure has been found to occur when the projectile strikes bone: this predictably deforms the bullet more than soft tissue..."

The testing I find most interesting is the Linebaugh Seminar, and the "Bone Box" where a large cow leg bone is placed in front of wet newspaper. And then some serious ammunition/bullets are tested for penetration. Very interesting results.

Mike: Good point about the bone hydration. That should be taken into account. Also, the bone simulant should also be placed within the gel block instead of outside it. Ribs are anywhere from 0.5" to 1" under the tissue. The testing should represent that.

These academic arguments rapidly degrade. Whether you like M&S or Fackler, Roberts or Wolberg every one of them has or had an agenda, as such their "data" is questionable. Fackler was fired by the FBI after they saw smoke and mirrors.

I also like to use anecdotal data provided by police departments in after action reports. No data set is perfect. Gelatin is a great tool if used correctly with a control. Every valid scientific experiment has a control, the experimental data cannot stand by itself.

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